1. Field of the Invention
The present invention relates to an ink-jet head that discharges ink on a recording medium.
2. Description of the Related Art
A known ink-jet head includes a cavity plate formed of five plates piled and bonded together with adhesive agent, and a piezoelectric actuator bonded to the cavity plate. A base plate included in the cavity plate the ink-jet head includes pressure chambers, distal end flow channels formed at one end of the respective pressure chambers, opposite end flow channels formed at the other ends of the respective pressure chambers, and elongated portions serving as ink flow channels for placing the pressure chamber and the opposite end flow channels in fluid communication. The base plate includes opposing release grooves formed between the elongated portions, and substantially arcuate-shaped release grooves surrounding a side edge of each of the opposite end flow channels. The opposing release grooves are in fluid communication via release holes which penetrate through the base plate.
In a known configuration, when the base plate and a spacer plate adjacent to the base plate are bonded with adhesive agent, excessive adhesive agent is attracted toward the release grooves having a small cross-sectional area and hence generating capillary force larger than the portions having a large cross-sectional area. In a known ink-jet head, when the pressure chambers are arranged at a higher density, the distances between the pressure chambers, between the distal end flow channels, and between the opposite end flow channels are reduced. When the distance between the opposite end flow channels is reduced, it may become difficult to rest the release grooves formed between the opposite end flow channels on the base plate while leaving a bonding margin for connecting the opposite end flow channels and through holes formed through the spacer plate. Then, the release grooves formed between the squeezed portions may not connect to the arcuate-shaped release grooves. When the release grooves are isolated, air in the release grooves may be trapped when the base plate and the spacer plate are bonded with the adhesive agent, and the excessive adhesive agent may be attracted toward the squeezed portions where air tends to be released, and the excessive adhesive agent may clog the elongated portions.